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In smart and sustainable cities, smartness of buildings is expected to evolve. A smart building should enhance its users’ productivity and minimize its environmental impact. Although these objectives are seemingly common, the development of the smartness of buildings is actualized in the form of an incoherent combination of standards and solutions. The emergence of the IoT (Internet of Things) is expected to bring major improvements in the development of smartness, but at the same time, it may even worsen non-systematicity. Such inconsistency creates barriers to the commercialization of innovations and poses challenges to technical building management. Here, we clarify the situation between the conventional building management system approach and the IoT-based entrants. We analyze the different approaches to building automation systems’ interoperability by means of a literature review, professional interviews and smart readiness indicator impact evaluation. The study forms a general view based on the presented information and suggests approaches for specifying technical building systems, which are expected to improve their schematic clarity and reduce performance gaps of buildings. This study can be used as a practical tool by technical building managers, and it discusses issues needing consideration to the benefit of policymakers, industry and academia.

Purpose To compare and contrast mechanical properties of experimental alkali-resistant (AR) glass fibre-reinforced composites (FRCs) silanised with one of three functional trialkoxy silanes: 3-methacryloxypropyltrimethoxysilane (3-MPS), 8-methacryloxypropyltrimethoxysilane (8-MOS) and 3-acryloxypropyltrimethoxysilane (3-APS). The experimental AR-FRCs were silanised with or without plasma pretreatment. Materials and methods Continuous unidirectional AR-glass fibres (ARcoteX® 5326 2400tex, Owen Corning) were cleaned ultrasonically, treated either with or without cold plasma (Piezobrush® PZ2, Relyon Plasma, Germany), then silanised by immersion for 10 min in activated, hydrolysed silane solution containing either 3-MPS, 8-MOS or 3-APS. The fibre bundles were next air-dried (24 h), and dried in vacuum oven (80 °C, 5 kPa, 2 h), producing 6 types of silanised AR-glass fibres. Next, silanised AR-glass fibres were laminated with a resin matrix, bis-GMA:TEGDMA at 60:40 wt%, CQ at 0.7 wt%, DMAEMA at 0.7 wt%) for 10 min and paired randomly in rovings of two in stainless steel moulds (2 mm × 2 mm × 25 mm) to prepare an AR-FRC beam specimen (n = 16). All specimens were light-cured from the top and bottom directions for 60 s (Elipar S10, 3M ESPE). Half of the samples (n = 8) underwent accelerated artificial ageing by immersion in boiling water (100°C, 16 h). Finally, 12 experimental AR-FRC groups were produced. All specimens were subjected to the three-point bending test with the upper surface (facing curing light) towards the cross-head. After testing, fibres, silanised and non-silanised, were inspected under scanning electron microscopy (SU1510, Hitachi, Tokyo, Japan). Statistical analysis was performed with three-way ANOVA and the Tukey post hoc test at α = 0.05. Results The flexural modulus, flexural strength and fracture work of the materials were significantly affected by silane type (p < 0.05) and artificial ageing (p < 0.001). Plasma treatment on AR-glass fibres significantly reduces flexural modulus of FRC (pConclusion Long chain silanes impart higher flexural strength and lower flexural modulus to AR-FRCs. While artificial ageing halves flexural strength and plasticises them, plasma surface pre-treatment of AR-glass fibres before silanisation reduces the plasticising effect.

Purpose To investigate mechanical properties of experimental resin composites contain 8-methacryloxyoctyltrimethoxysilane (MOS) and a commonly used silane, 3-methacryloxypropyltrimethoxysilane (MPS). Materials and methods MOS and MPS were hydrolysed in 95vol% ethanol solution at pH 4 for 1h before silanisation of SiO2-based bioactive glass powder fillers (Ø 1.0µm, Schott, Germany) at 3, 6, 9 and 12wt% of silane. After drying in a vacuum oven (80°C, 5kPa, 2h) they were mixed with a monomer mixture of urethane dimethacrylate and triethylene glycol dimethacrylate in a 70:30 weight ratio, camphorquinone 0.7wt% and 2-(dimethylamino)ethyl methacrylate 0.7wt% to produce eight experimental groups of resin composites with a filler load of 72.7wt%. After photopolymerisation for 25 min and post-curing at room temperature (24h), uniform rectangular beams were cut out for the three-point bending test (2mm × 2mm × 25mm, n = 8). The surface Vickers microhardness (VHN) test (press-load 2.94N for 10s, n = 6; Duramin 5, Struers) was performed before observation under 3-D optical microscopy. Statistical analysis was performed using ANOVA followed by the Tukey post hoc test (p

This in vitro study aimed to evaluate the shear bond strength (SBS) of particulate filler composite (PFC) to saliva- or water-contaminated fiber-reinforced composite (FRC).One type of FRC substrate with semi-interpenetrating polymer matrix (semi-IPN) (everStick CB) was used in this investigation. A microhybrid PFC (Filtek Z250) substrate served as control. Freshly cured PFC and FRC substrates were first subjected to different contamination and surface cleaning treatments, then the microhybrid PFC restorative material (Filtek Z250) was built up on the substrates in 2-mm increments and light cured. Uncontaminated and saliva- or water-contaminated substrate surfaces were either left untreated or were cleaned via phosphoric acid etching or water spray accompanied with or without adhesive composite application prior applying the adherent PFC material. SBS was evaluated after thermocycling the specimens (6000 cycles, 5°C and 55°C).Three-way ANOVA showed that both the surface contamination and the surface treatment signficantly affected the bond strength (p0.05). Saliva contamination reduced the SBS more than did the water contamination. SBS loss after saliva contamination was 73.7% and 31.3% for PFC and FRC, respectively. After water contamination, SBS loss was 17.2% and 13.3% for PFC and FRC, respectively. The type of surface treatment was significant for PFC (p0.05), but not for FRC (p = 0.572).Upon contamination of freshly cured PFC or semi-IPN FRC, surfaces should be re-prepared via phosphoric acid etching, water cleaning, drying, and application of adhesive composite in order to recover optimal bond strength.

Light transmittance of dental composites varies between products and shades, but also light curing units differ to each other in their irradiance and fiber optic structure of curing tip. The aim of this study was to investigate whether there is linear relationship between the distance of the curing tip to the resin composite and irradiance at lower surface of the resin composite.Disks of 1 mm thickness (6mm diameter) were fabricated. Light transmittance (intensity) through the disk was measured at distance of 0, 2, 4, 6, 8, 10 mm from the light tip with two light curing units Elipar S10 (3M-ESPE) and Silverlight (GC). Irradiance ratio (irradiance on the sensor surface without the composite disk / with the composite disk) was calculated and plotted against the distance of the light curing tip. Statistical analysis was carried out using analysis of covariance (ANCOVA, Tukey's, α =0.05).Irradiance ratio varied between 18% to 24% with Silverlight and 21% to 26% with Elipar S10 light curing units. There were statistically significant differences between the ratios with different distances of the light curing tip (p⟨0.05). Interestingly, the highest irradiance ratio for Elipar S10 unit was found with 4 mm distance of the tip, whereas Silverlight unit had the highest ratio with 6 mm distance. Out of two tested resin composites, the flowable composite showed higher irradiance ratio than regular packable resin composite.Increase of distance of the light curing tip from the composite surface decreased the absolute irradiance underneath of composite, as expected. However, there seemed to be device dependent optimal distance of 4-6 mm to reach the most efficient irradiance ratio through the composite resin keeping in mind that most efficient transmission of light through the material is reached by having light curing tip in contact to the material.

To evaluate the light transmission characteristics of different types, shades, and thicknesses of novel CAD/CAM materials and their effect on the degree of conversion (DC) of a dual-curing resin cement.Square specimens (12 × 12 mm2) of three CAD/CAM materials - GC Cerasmart, Lava Ultimate, Vita Enamic - of different thicknesses (1.00, 1.50, and 2.00 mm, n = 5 per thickness) were irradiated with an LED unit. The amount of transmitted light was quantified. Thereafter, the DC% of the dual-curing resin cement (RelyX Ultimate) was recorded after 15 min using Fourier transform infrared spectroscopy. Statistical analysis was performed using two-way ANOVA followed by the Tukey's HSD post-hoc test at a significance level of p 0.05. Regression analysis was performed to investigate the correlation between the DC and radiant energy, and the DC and thickness.Although the type and shade of CAD/CAM material significantly affect transmitted light irradiation (p 0.0001), degrees of conversion are similar when the CAD/CAM material or material shade were taken into consideration (p 0.05). Conversely, material thickness significantly affected light transmission (p 0.0001) and DC (p 0.0001). Multiple effects of material, shade, and thickness did not significantly affect the evaluated parameters (p = 0.638 for light irradiation; p = 0.637 for DC). Linear regression analysis showed a correlation between delivered energy and DC% results of the Vita Enamic (R² = 0.4169, p 0.0001).Reduced light transmission in 2-mm-thick specimens of all CAD/CAM materials indicates that proper curing of the cement beneath CAD/CAM materials should be ensured.

Fiber-reinforced composites (FRC) can potentially help in a physiologic stress transmission due to its excellent biomechanical matching with living tissues. Novel one-piece FRC implants and abutments with two different fiber orientations were loaded until failure to assess the load-bearing capacity, fracture patterns, and precision of fit. The one-piece FRC implants showed significantly higher load-bearing capacity compared to FRC abutments regardless of the fiber orientation (p0.001). For FRC abutments, bidirectional abutments showed significantly higher loads compared to unidirectional abutments (p0.001). The type of structure and fiber orientation are strong determinant factors of the load-bearing capacity of FRC implants and abutments.

The aim was to compare the intensity of artefacts in CBCT images caused by different percentages of radio-opacifying material in composite simulation models of implants. Titanium and zirconia models of implants were used as a reference for the evaluation of the intensity of artefacts.Seven different percentages of radio-opacifying BaAlSiO2 fillers were added to composite resin to fabricate seven step wedges and simulation models of implants. Titanium and zirconia simulation models of implants were also fabricated. Aluminium step wedge was used as a reference for the measurement of grey values in intraoral radiographs. Step wedges were exposed with a Planmeca Intra X-ray machine (Planmeca Oy, Helsinki, Finland). All composite, titanium and zirconia simulation models of implants were exposed with a SCANORA(®) 3D dental X-ray machine (Soredex, Tuusula, Finland). Images and grey values were analysed with ImageJ software (National Institutes of Health, Bethesda, MD). To demonstrate possible artefacts between all the simulation models of implants, the images were also visually compared with each other using ImageJ software.Artefacts were clearly present in CBCT images caused by titanium and zirconia and when the composite material consisted at least 20% BaAlSiO2. The intensity of artefacts increased when the radio-opacity of the composite material increased.Materials containing less radio-opacity produce less pronounced artefacts. The cut-off point for artefacts is at 20% radio-opaque filling material in composite material.

Satellite-based positioning is becoming the prevalent solution for positioning and alignment of drill holes in open pit mines, quarries and construction sites. This is due to the accuracy and convenience of the systems, leading to improved blasting quality and thereby reduced costs and improved productivity. In a conventional hole navigation system, the operator is assisted by precision sensors and a satellite positioning receiver which compare the boom position and attitude to those pre-defined by a drilling plan. While such an approach provides a superior accuracy of the holes in comparison to conventional systems, the boom still has to be positioned manually using the rig controls. This work describes an automatic hole positioning and alignment system developed for drill rigs. The novelty of the solution is in the surface drilling application and the versatility of a typical drill boom. The system has been tested both in a simulated and a prototype environment. The main result is that automatic positioning improves the positioning accuracy and reduces the time required for the positioning task. This is because the automatic system overcomes the main restrictions of manual operation, namely the time and attention needed to position the boom given its dynamics and the actuator-based controls. Furthermore, the operation of the automatic positioning system is effortless and fast. These developments lead to further improvements in drilling quality, which in turn yields better blasting results and higher productivity in excavation. The developed system is also an essential part of remote operated or autonomous drill rigs.

This study aimed to evaluate the micro push-out (μ-PO) bond strength between zirconia and resin cement after addition of zirconia particles to increase the surface roughness.Y-TZP zirconia specimens in three experimental groups were subjected to Y-TZP particle deposition via dipping into the milling residue suspension at different times prior to the sintering process. The dipping procedure was repeated twice for each specimen in group B, six times in group C, and ten times in group D. The specimens subjected to airborne-particle abrasion (110 μm Al2 O3, Rocatec Pre) acted as the control group (group A). All of the specimens were then bonded using adhesive resin cement (RelyX Ultimate). A μ-PO test was used to determine the bond strength values. One-way ANOVA at a 5% confidence level was performed for data analysis. Optical microscopy and scanning electron microscopy (SEM) were used to evaluate the failure modes and surface structure.Y-TZP particle deposition did not have a significant effect on the bond strength of the resin cement to zirconia specimens when compared to the control (p = 0.141). Higher bond strength values were observed in groups C and D than in control. The surface layer presented blister-like porosities with openings of various diameters ranging between 2 and 4 μm.Y-TZP particle deposition after dipping six and ten times did not improve the mean bond strength statistically but presented surface topography that may be favorable for increased micromechanical retention for adhesive resin cement.Y-TZP particle deposition may create a more retentive surface than airborne-particle abrasion for adhesive bonding between zirconia surface and resin cement.

To estimate the surface gloss of various dental nano composites by using the correlation between deltaE* specular component excluded (SCE) - specular component included (SCI) and surface roughness (Ra).Two brands of commercial and two experimental light-cured resin composites were used. Resin composite discs were prepared 10 mm in diameter and 3 mm in thickness. 56 subgroups (n=5) were designed according to two different curing conditions (hand light curing and additional post-heat curing) and seven different polishing methods (Mylar, 4000-, 2400-, 1200- and 320- SiC paper, rubber-based silicone, three-step polishing kit). deltaE*SCE-SCI and Ra measurements were done. Two specimens in each subgroup were analyzed by SEM. Multifactorial ANOVA and post hoc Tukey test were applied for the evaluation of the deltaE*SCE-SCI and Ra data (P0.05). Moreover, Spearman's rank correlation test was used to determine the correlation between deltaE*SCE-SCI and Ra results (P0.01).A strong correlation was found between deltaE*(SCE-SCI) and Ra results indicating the surface gloss of the tested composite resin materials after different curing and surface polishing methods. A three-factor interaction was found between curing conditions, surface polishing methods and resin composites (P0.05) in deltaE*SCE-SCI and Ra results. Additionally, significant differences were found between composites and between polishing methods (P0.05). Furthermore, there were significant differences between curing conditions in Ra results (P0.05).

To evaluate the translucency characteristics of new flowable bulk-filling resin composites at various thicknesses. Experimental short fibre-reinforced composite was also tested.Two new brands of flowable bulk composites (Venus Bulk Fill and SureFil SDR Flow), experimental short fibre-reinforced resin composite (FC) and, as control, conventional flow (Filtek Supreme Flow XT A3) and universal (Filtek Universal Supreme XTE A3B) resin composites were investigated. Translucency parameter was calculated for various thicknesses of composite (1, 2, 3, 4, 5 and 6 mm) over white and black backgrounds using spectrophotometry to determine the CIELAB values of each specimen. Data were statistically analysed with analysis of variance.Translucency values significantly correlated with thickness of resin composite specimens (P0.05). For the new types of flowable bulk-filling material, translucency was observed for thicknesses up to 5 to 6 mm, whereas for experimental FC composite, the effect was observed up to 4 to 5 mm, and for control flow and universal filling composites, up to 2 to 3 mm.New flowable bulk-filling resin composites have less masking ability than conventional universal filling resin composite materials, which should be taken into account when optimum colour match and aesthetic results are to be achieved.

To compare the load-bearing capacity of custom-made zirconia abutments with that of prefabricated commercially available zirconia abutments.Zirconia (ICE Zircon) blocks were manually copy-milled to abutments using prefabricated commercially available abutments as models, divided into four groups (n = 10/group), and sintered at 1,500°C. Prefabricated commercially available abutments were used as controls (groups 1 and 4, n = 10/group). The abutments in the study groups were: (1) Astra ZirDesign (AstraTech); (2) copy-milled Zirkonzahn-Astra; (3) copy-milled Zirkonzahn-Astra, short; (4) Xive Cercon (Dentsply/Friadent); (5) copy-milled Zirkonzahn-Xive; and (6) copy-milled Zirkonzahn-Xive, modified. Seven abutments per group were screwed onto implant replicas (size 3.5/4.0 mm for AstraTech, 3.8 mm for Dentsply Friadent) with acrylic resin sample base; the implants were loaded dry with a universal testing machine at room temperature and a 45-degree loading angle. Statistical analyses were made using one-way analysis of variance. The three remaining abutments per group were screwed onto implant replicas, and the distance between the replica and the abutment was measured with a scanning electron microscope.Significant differences were seen among the groups in terms of load-bearing capacity; copy-milled Zirkonzahn-Xive modified abutments (group 6) were statistically significantly stronger (1,099 N) than the other abutments (P.05). The Xive models resulted in catastrophic failure, whereas the Astra-design revealed visual bending before failure.Custom-made zirconia abutments have comparable failure loads to those seen for prefabricated commercially available zirconia abutments.

This study evaluated bond strengths of four soft liners to fiber-reinforced (FR) and unreinforced poly methyl(methacrylate) (PMMA) denture-base resin.The autopolymerized denture-base resin Palapress Vario (Heraus Kulzer GmbH, Hanau, Germany) was used as the substrate (15 × 15 × 5 mm³). The test group consisted of substrates reinforced with porous PMMA preimpregnated unidirectional glass fibers (Stick [StickTech, Turku, Finland]) (PMMA + FR group), and the control group was unreinforced acrylic resin (PMMA group) (n = 80 per group). One of four soft liners (Ufi Gel SC [Voco, Cuxhaven, Germany], Sofreliner Tough [Tokuyama Dental Corporation, Tokyo, Japan], Vertex SoftSil 25 [Vertex-Dental B.V., Zeist, The Netherlands], and Eversoft [Dentsply Austenal, York, PA]) was placed and cured between two substrates using a polyethylene ring (10 mm inner radius, 3 mm height). Tensile bond strength tests (crosshead speed = 10 mm/min) were performed, and the results were analyzed using analysis of variance followed by Tukey's test (p= 0.05). Fracture surfaces were categorized as adhesive or cohesive-mixed modes, and failure types were statistically analyzed using chi-square test.FR did not affect the bond strength results significantly (p0.05) except for Ufi Gel SC. Significant differences in bond strength were found among the reline materials (p0.001). FR specimens showed a significantly higher number of cohesive-mixed fractures compared to unreinforced specimens (p0.05), except for plasticized acrylic-based reline material (Eversoft [Dentsply Austenal]), which showed fewer cohesive-mixed failures with FR.The choice of appropriate reline material system with FR acrylic resin is important for the soft liner/denture-base polymer bond. Glass FR did not have a decreasing effect on the bond strength, except for Ufi Gel SC.

This study was conducted to evaluate the microtensile bond strength of composite resin to dentin with experimental rigid rod polymer (RRP) modified primers. RRP fillers are based on long stiff molecules specifically designed to create long polymers with restricted chain movement.Experimental primers were fabricated by dissolving RRP into dichloromethane (DCM) and further mixing it with monomers: ethylene glycol methacrylate phosphate (EGMP), bis[2-(methacryloyloxy)-ethyl]phosphate (BMEP) and 3(methacryloyloxy)propyltrimethoxysilane (MPS). Eight experimental primers were prepared with different proportions for each dentin substrate. A commercial etch-and-rinse adhesive was used as a control. Surfaces of human molar teeth were wet ground occlusally. The experimental primers were applied onto dentin prior to light polymerization of the incremental composite resin build-up. After 48 hours of water storage, teeth were sectioned and tested with the microtensile tester. Fracture surface analysis and contact angle measurements of adhesive resin were performed. Scanning electron micrographs were taken.3-way ANOVA revealed that all factors, monomer type, solvent-monomer ratio and RRP, had a significant effect (p0.05) on bond strength. Primer with a combination of MPS and dimethacrylate BMEP revealed higher bond values than a mixture of MPS and monomethacrylate EGMP. Increase of the solvent-monomer ratio and addition of RRP into primers increased the microTBS.The contact angle measurements showed that RRP containing primers enhanced adhesive resin penetration into dentin similar to that of the control primer. Within the limitations of this study, it was concluded that an experimental type of modified RRP-silane-phosphate-acrylate primer was developed with comparable bonding properties to a commercial control.

To investigate the effect of high frequency ultrasonic agitation on the microtensile bond strengths of different self-etching adhesives.Thirty-six human molars were wet ground occlusally until dentin was exposed. The one-step self-etching adhesives Clearfil S3 Bond, G-Bond, and Futurabond NR were tested in this study. In the control groups, bonding procedures were performed according to the manufacturers' instructions. In the experimental groups, bonding materials were applied with a 1 MHz therapeutic ultrasonic device on the dentin surfaces. The composite crown was built up incrementally to a height of 5 mm. Each tooth was serially sectioned into rectangular beams, and the specimens were subjected to microtensile testing. Failure modes were observed under a stereomicroscope and classified. Randomly selected specimens from each group were observed with SEM.Two-factor ANOVA indicated that both the adhesive system and the ultrasonic agitation effect influenced bond strength (p0.05). The bond strength of G-Bond adhesive to dentin was higher after ultrasonic agitation (p0.05), whereas ultrasonic agitation of Futurabond and S3 Bond did not affect bond strength values (p0.05). Failure after the test was commonly due to adhesive failure in the dentin.High-frequency ultrasonic agitation of self-etching adhesives during their application may enhance their bonding performance.

To investigate the effects of an interfacial fiber-reinforced resin-based material (FRRM) application and different light-curing modes on the bond strength of a thermoplastic synthetic polymer-based root canal filling material (Resilon) to a methacrylate-based sealer (Epiphany).One hundred Resilon disks were prepared and divided into two experimental groups: 1. application of FRRM (EverStick Net) on the Resilon surface, and 2. Resilon alone (control). Following subsequent application of the Epiphany sealer, the specimens were randomly assigned into 3 subgroups according to the curing method employed: 1. chemical curing, 2. quartz-tungsten-halogen (QTH) light, and 3. light-emitting diode (LED). The latter two groups were further subdivided to test the effects of two different polymerization modes for each light-curing unit. Cured specimens were subjected to shear bond strength testing and the failure modes were examined. The data were analyzed with three-way analysis of variance (ANOVA).Regardless of the curing method tested, application of FRRM at the interface significantly increased the bond strength of Resilon to Epiphany (p0.001). Bond strength values (MPa) were as follows (mean +/- SD): 1. chemical curing with FRRM= 3.0 +/- 0.4, without FRRM = 1.2 +/- 0.3; 2. QTH: a) standard mode with FRRM = 8.6 +/- 0.6, without FRRM = 5.5 +/- 0.9; b) ramp mode with FRRM = 8.0 +/- 1.0, without FRRM = 5.3 +/- 1.4; 3. LED: a) standard mode with FRRM = 8.8 +/- 1.1, without FRRM = 5.4 +/- 1.0; b) exponential mode with FRRM = 8.5 +/- 1.0, without FRRM = 4.6 +/- 0.6. Although light curing of specimens significantly increased the bond strength of Resilon to Epiphany (p0.001), the type of light-curing unit and different curing modes had no significant influence on bond strength (p = 0.852 and p = 0.776, respectively).The highest bond strength values were obtained when the FRRM was used at the interface and the sealer was light cured.

This study investigated the effects of two types of loading conditions on mechanical behavior of the pontic of composite fixed partial denture (C-FPD) and fiber reinforced composite fixed partial denture (FRC-FPD). Two types of FE model of posterior bridge were developed. Two types of loading conditions, i.e. vertical 629 N, and lateral of 250 N, were used. In lateral load, displacement was showed a similar behaviours. However in vertical load, displacement of FRC-FPD was less than C-FPD. These results clarified the magnitude, distribution of stress and displacement generated in C-FPD and FRC-FPD of pontic caused by two different loading conditions.

The aim of this study was to investigate the optimal design of a fiber-reinforced composite (FRC) framework to obtain the maximum reinforcement for fixed partial dentures (FPDs) under three different loading conditions using three-dimensional finite element (FE) analysis. materials and methods: A three-unit FPD replacing the maxillary right lateral incisor was constructed using FE analysis software (ANSYS 10.0, ANSYS). A fiber framework of the pontic was designed with three variations: with the main framework curved labially (FRC1), located in the center (FRC2), or curved lingually (FRC3). Each framework was compared with a hybrid composite FPD without any fiber reinforcement (C-FPD). A lateral load was applied to the three different loading points of the pontic 0 mm, 3 mm, and 6 mm from the incisal edge, each representing loading conditions 1, 2, and 3, respectively.Localized high stress concentration was observed around the connectors under all loading conditions. In all FRC-FPD models, the FRC framework showed stress-bearing capacity for the FPD. The highest stress reduction ratio under all loading conditions was obtained using the FRC1 model. The FRC1 framework also best reduced displacement of the framework.This study suggests that the optimum design of an FRC framework is to labially curve the FRC of the main framework at the region of the pontic.

Although all-ceramic restorations have become popular, they present some biomechanical problems. Some technical failures can be repaired intraorally to help maintain the longevity of the restoration. This clinical report describes an intraoral method for repairing a fractured 4-unit posterior zirconia-based ceramic fixed partial denture using fibre-reinforced composite material.

The aim of this study was to evaluate stress distribution in anterior adhesive fixed dental prostheses (FDP) and at the tooth/framework interface. Metal (M-FDP) and glass fiber-reinforced composite (FRC-FDP) frameworks were compared.The design of the FDP consisted of retainers on a maxillary central incisor and canine with a pontic of a lateral incisor. Two different framework materials were compared: isotropic Au-Pd alloy and anisotropic continuous unidirectional E-glass FRC. Veneers in both cases were made of isotropic veneering hybrid composite. A 3-dimensional finite element model of a 3-unit FDP loaded with 154 N (at a 45-degree angle to the incisal edge of the pontic) was used to analyze stress distribution in the FDP and at the adhesive interface. A finite element analysis was used in calculation of the maximum principal stress and displacement.The maximum displacement of FRC-FDP was higher than that of M-FDP. Stress concentrations were located equally in the connectors and at the occluding contact points in both framework types. Maximum principal stress of FRC-FDP was lower than that of M-FDP. Stress analysis further indicated that the maximum stress in the luting cement interface of FRC-FDP was located at the middle part of the retainers, whereas in the M-FDP, the maximum stress was located at the marginal edge of the retainers.The FE model revealed differences in displacement and stress distribution between metal and FRC frameworks of FDP. The general observation was that FRC-FDP provided more even stress distribution from the occluding contact point to the cement interface than did M-FDP.

The aim of this study was to evaluate the stress distribution at the marginal edge of metal-free crowns using 2 different materials (ceramic and hybrid composite) and 4 different preparation designs (knife edge, chamfer, heavy chamfer, rounded shoulder). All marginal preparation designs for hybrid composite crowns showed lower compression and tensile stress than the ceramic crowns. The rounded shoulder preparation provided more even stress distribution than the knife-edge preparation. Heavy chamfer was an acceptable preparation design for ceramic crowns. The chamfer preparation was preferred for hybrid composite crown.

The aim of this study was to evaluate the design of fiber-reinforced composite (FRC) on some mechanical properties of a dental implant.FRC implants were fabricated using different polymerization conditions and designs of the glass-fiber structure. Specimens were tested with a cantilever bending test and a torsional test. The degree of monomer conversion (DC%) was measured using a Fourier transform infrared spectroscopy (FTIR).Statistical analysis showed significant differences between groups revealing mean fracture load values from 437 N to 1461 N. The mean torsional force in fracture varied from 0.01 to 1.66 Nm. The DC% varied from 50% to 90%.This study suggests by modifying the polymerization conditions and fiber orientation of FRC implants, the biomechanical properties of an FRC can be tailored to the needs of dental implants.

The purpose of this study was to investigate the reinforcement effect of short E-glass fiber fillers on some mechanical properties of temporary crown and bridge (TCB) composite resin with a semi-interpenetrating polymer network (semi-IPN).Experimental temporary fiber reinforced (TFC) composite resin was prepared by mixing 15 wt% of short E-glass fibers (3 mm in length) with a 35 wt% of semi-IPN-resin (dual or chemical cure) with 50 wt% of silane treated particulate silica fillers using a high speed mixing device. Temporary crowns (n=6) and test specimens (2 x 2 x 25 mm3) (n=6) were made from the experimental TFC and conventional TCB composite (control, Protemp Garant, 3M-ESPE, St. Paul, MN, USA). A three-point bending test was done according to ISO standard 10477, and a compression loading test was carried out using a steel ball (Ø 3.0 mm) with a speed of 1.0 mm/min until fracture occurred. The degree of monomer conversion (DC%) of both composites was determined by Fourier transfer infrared (FTIR) spectrometry.The analysis of variance (ANOVA) revealed both dual and chemical cure experimental TFC composite resins had statistically significant (p0.05) higher flexural strengths (117 and 99 MPa, respectively) and compressive load-bearing capacity (730 and 623 N, respectively) compared to the control TCB composite resin (72 MPa, 549 N).The use of short fiber fillers with semi-IPN polymer matrix yielded an improved mechanical performance compared to a conventional TCB composite resin.

The aim of this study was to compare the attachment of different composite resin luting cements to a fiber-reinforced composite (FRC) post with a semi-interpenetrating polymer network polymer matrix.Six different brands of composite resin luting cement stubs were applied on the surface of FRC post material and light-cured for 40 seconds. Shear bond strengths of luting cement stubs were measured using a universal testing machine.The differences in shear bond strengths between the cements were not statistically significant.All of the tested composite resin luting cements provided acceptable attachment to the tested FRC post. The tested FRC post material is suitable to use with different composite resin luting cements.

The reliability requirements and the role of the supervisory authority in the electricity distribution business have grown strongly in the past few years. Electricity distribution companies are forced to consider new investment strategies to meet the challenges arising from the new operational environment. Aged electricity networks are subject to the more challenging weather conditions. To meet the new requirements, the traditional line extension approach is no longer an acceptable and sustainable planning method. There are various new technical solutions and methods to develop electricity networks. In this paper, different kinds of electricity distribution investment strategies in the modern business environment are studied. Strategies are based on several new technical innovations successfully implemented in Finnish electricity distribution companies. Methods such as roadside networks, 1000 V low voltage system, underground cables and low-cost primary substations are exploited successfully in the long-term planning process.

To investigate the effect of different light-curing units and adhesive systems on the bonding of leucite ceramic to dentin.Flat dentin surfaces were ground occlusally on human molars (n = 60). Hot-pressed ceramic blocks of IPS Empress (Ivoclar-Vivadent) were fabricated, air-particle abraded, and cleaned in distilled water. Following acid etching and silane treatment of ceramic, bonding procedures were performed. The teeth were divided into two groups according to the type of the adhesive system: (1) total-etch: etchant (Etch 37) and adhesive (One Step Plus); (2) self-etching: self-priming etchant (Tyrian SPE) and adhesiveOne Step Plus) (n = 30). Ceramic blocks were bonded to the dentin surfaces with dual-polymerizing resin luting cement (Duolink). For polymerization, the QTH (Blue Swan Digital, Dentanet) was used in soft-up and high-power mode, the LED (Elipar Freelight 2, 3M Espe) in exponential and standard mode, and the PAC (PlasmaStar, SP-2000, Monitex) in normal and ramp-curing mode (n = 5). Following storage in distilled water for 24 h, the samples were thermocycled for 6000 cycles. The bonded specimens were serially sectioned and trimmed to hourglass shapes with approximately 1.6 +/- 0.16 mm2 cross-sectional areas, then tested with the microtensile tester at a rate of 1 mm/min. Fracture surfaces (were analyzed with SEM. The data were analyzed with three-way analysis of variance (ANOVA).ANOVA revealed that adhesive systems (p0.001) and light-curing units (p = 0.015) had a significant effect on bond strength values. Bond strength means (+/- SD) in MPa were as follows: total-etch system: QTH/soft-up mode = 16.2 (5.4); QTH/high power mode = 15 (5.4); LED/standard mode = 12.1 (3.3); LED/exponential mode = 15 (5); PAC/normal mode = 19.3 (7); PAC/ramp-curing mode = 19.6 (7.4). Self-etching system: QTH/soft-up mode = 9.9 (2.1); QTH/high-power mode = 12.5 (4.3); LED/standard mode = 8.6 (2); LED/exponential mode = 13 (3.8); PAC/normal mode = 13.1 (3.9); PAC/ramp-curing mode = 8.9 (2.2).Results indicated that the conventional total-etch system provided more reliable bonding compared to the self-etching system. The PAC light-curing unit together with the total-etch adhesive system showed the highest mean micro-TBS values with either normal mode or ramp-curing mode.

The aim of this study was to determine the compressive fatigue limits (CFLs) of fractured incisor teeth restored using either a conventional adhesive-composite technique or using fiber-reinforced composites (FRCs).Fifteen extracted sound upper incisor teeth were prepared by cutting away the incisal one-third part of their crowns horizontally. The teeth were restored using three techniques. Group A (control group) was restored by reattaching the original incisal edge to the tooth. Group B was restored using particulate filler composite (PFC). Group C was restored with PFC and FRC by adding a thin layer of FRC to the palatal surface of the teeth. The bonding system used was a conventional etch system with primer and adhesive. All restored teeth were stored in water at room temperature for 24 h before they were loaded under a cyclic load with a maximum controlled regimen using a universal testing machine. The test employed a staircase approach with a maximum of 103 cycles or until failure occurred. Data were analyzed using analysis of variance (ANOVA) (p=0.05). Failure modes were visually examined.Group A (reattaching fractured incisal edge) revealed the lowest CFL values, whereas the creation of a new incisal edge with PFC revealed a 152% higher CFL value compared to Group A. Group C (teeth restored with FRC) revealed a 352% higher CFL than the control group. ANOVA revealed the restoration technique significantly affected the compressive fatigue limit (p0.001). The failure mode in Group A and B was debonding of the restoration from the adhesive interface. While in Group C, the sample teeth fractured below their cemento-enamel junctions.These results suggested an incisally fractured tooth restored with the combination of PFC and FRC-structure provided the highest CFL.

To study the fracture behavior of direct resin composite crowns with or without experimental fiber reinforcement.Clinical crowns of single-rooted maxillary premolars were cut off at the cemento-enamel junction. Canals were prepared with Gates Glidden drills up to size 4. No additional post-space preparations were made. Roots were embedded in acrylic and canal entrances were standardized (depth 2 mm, diameter 1.75 mm). Three groups of 14 samples were treated as follows: (1) custom-made glass FRC post (EverStick Post); fibers 5 mm deep in the canal, (2) similar post-system as (1) with incorporation of a new type of glass fiber fabric, (3) no fiber reinforcement (control). Posts were cemented with resin cement (Panavia F). Resin composite crowns (Filtek Z250) were made using an anatomically formed mold. Static load until fracture was applied using a universal loading device with a cylindrical bar (diameter 2 mm) with a crosshead speed of 5 mm/minute (loading angle: 30 degrees to the tooth long-axis). Failure modes were categorized as favorable and unfavorable failures.There was no significant difference in mean failure loads among the four groups (P0.05). Favorable failures occurred significantly more often in Group 2 than in the other groups (P0.05). The results suggest that an incorporated glass fiber fabric does not affect the load-bearing capacity of resin composite complete crowns on structurally compromised and non-vital premolars. Incorporation of a glass fiber fabric, however, has a beneficial effect on the failure mode.